Applications of CNN for detecting crime from video surveillance cameras
After a bit of research I found something kind of close:


Artificially intelligent security cameras are spotting crimes before they happen
New surveillance cameras will use computer eyes to find 'pre crimes' by detecting suspicious behaviour and calling for guards
CCTV 'fightcams' detect violence 'before it happens'  at Dailymail, also check at Telegraph


They, however, makes no mention of what specific methods they use.

So a crime detection system as that is written does not exist, but abnormal behaviour detection systems do.

An accurate generalized system seems intuitively infeasible, however. Commiting a crime, unlike falling, is a complex behavior, and takes so many forms. A camera watching a store's counter like at a 7-11 could perhaps see that the 'customer''s arm is strangely reaching across the counter, and the attendant is moving a lot more than usual suddenly, but aside from very specific cases like this such a system is currently quite unfeasible. 

Crimes are unusual, relatively speaking, and their dramatic nature means that even the simplest crimes play out in very different ways. Perhaps you could in this case you could try to look for images of a gun, or someone with their hands up. So, looking for unusual, detectable behavioural mannerisms may be possible, but not crime detection.

Ultimately, while you may be able to make (possibly pretty good) systems to detect specific crimes in specific environments, that's all we got for now.

P.S. - Do these camera's also get audio signals? That is also an interesting facet to consider ("PUT YOUR HANDS UP / GIVE ME ALL YOUR MONEY")